The present disclosure relates to a semiconductor device, and in particular, to a three-dimensional semiconductor memory device.
Higher integration of semiconductor devices is needed to satisfy consumer demands for superior performance and inexpensive prices for electronic products. Considering semiconductor devices, because their level of integration is an important factor in determining electronic product prices, an increased level of integration is especially needed. The level of integration of typical two-dimensional or planar semiconductor devices is mainly determined by the area occupied by a unit memory cell, which, in turn is greatly influenced by the technology of a fine pattern forming. Extremely expensive process equipment is used to increase pattern fineness, which sets a practical limitation on increasing the level of integration for two-dimensional or planar semiconductor devices. To overcome such a limitation, three-dimensional semiconductor memory devices that include three-dimensionally arranged memory cells have been recently proposed.